Multiturn Angle Sensing With K-Cycle Magnetic Pulse Counting
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Solution Overview
Problem
Existing multiturn angle detection devices are hindered by size and cost issues due to the need for multiple power generation sensors and complex signal processing, and they fail to accurately determine rotation direction when pulse missing occurs.
Innovation Solution
A multiturn angle detection device using a single power generation sensor, a magnetic field generation source, and a precision absolute angle detector, which generates a multiturn absolute angle detection value by combining count values without complex correction processes, utilizing a k-cycle alternating magnetic field to ensure precise angle detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple power generation sensors are used to detect rotation direction and prevent pulse missing, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent applies periodic action by using a k-cycle alternating magnetic field that generates 2k voltage pulses per rotation cycle. This periodic pulse generation ensures that at least one pulse is generated in each half-cycle, preventing pulse missing and enabling accurate rotation direction detection with a single sensor.
Solution Approach 2:
The patent changes the parameter of magnetic field cycling frequency by applying a k-cycle alternating magnetic field instead of a single-cycle field. This parameter change transforms the pulse generation pattern to ensure sufficient pulses are generated within each rotation cycle, solving the pulse missing problem without additional sensors.
2Device complexity
If a single power generation sensor is used, then device complexity and cost are reduced, but measurement precision deteriorates due to pulse missing and inability to determine rotation direction
Solution Approach 1:
The patent uses periodic k-cycle alternating magnetic field application to generate multiple voltage pulses per rotation cycle. This ensures that even with a single sensor, sufficient pulses are generated to accurately determine rotation direction and prevent pulse missing.
Solution Approach 2:
The patent employs feedback by counting the number of voltage pulses generated within each rotation cycle and using this count information to determine rotation direction. The system monitors pulse generation and uses the pulse count feedback to accurately track rotation direction changes.
3Measurement precision
If complex signal processing and correction processes are applied, then measurement precision is improved, but device complexity and processing time increase
Solution Approach 1:
The patent uses periodic k-cycle alternating magnetic field to generate a predictable pattern of 2k pulses per rotation. This regular pulse pattern simplifies signal processing because the system knows exactly how many pulses should be generated per cycle, eliminating the need for complex correction algorithms.
Solution Approach 2:
The patent performs preliminary action by pre-defining segment boundaries based on the known pulse generation pattern from the k-cycle alternating magnetic field. This allows the segment counter to be configured in advance with the expected number of pulses per cycle, simplifying the combining process with the absolute angle detector.
4Measurement precision
If k-cycle alternating magnetic field is applied to generate 2k voltage pulses per turn, then measurement precision is improved, but energy consumption increases
Solution Approach 1:
The patent applies periodic k-cycle alternating magnetic field where k is an integer. By optimizing k to be the minimum value needed for the application (e.g., k=1 or k=2), the system achieves sufficient measurement precision while minimizing energy consumption. The periodic nature allows for efficient pulse generation without continuous high-energy input.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The device achieves size and cost reduction while providing precise multiturn angle detection by using a single power generation sensor, ensuring accurate rotation direction determination even with pulse missing, and eliminating the need for complex signal processing.
Implementation Method 1
a power generation sensor including a magnetic wire that exhibits a large Barkhausen effect, and a coil wound around the magnetic wire, generates a voltage pulse according to a magnetic field change occurring due to the rotation of the magnetic field generation source
Implementation Method 2
Magnetic wires having a large Barkhausen effect (large Barkhausen jump) are known in the name of Wiegand wire or pulse wire
Data Source
AI summary
A multiturn angle detection device generates the multiturn absolute angle detection value of a rotating body. The multiturn angle detection device includes: a segment counter; a precision absolute angle detector; and an arithmetic device to generate the multiturn absolute angle detection value by combining the outputs of the segment counter and the precision absolute angle detector with each other. The segment counter includes: a single power generation sensor; a magnetic field generation source; a sensor element; and a nonvolatile memory to store a count value. The magnetic field generation source applies a k-cycle alternating magnetic field (wherein k is an integer not smaller than 3) per each turn of the rotating body axially of a magnetic wire. The arithmetic device uses the count value stored in the nonvolatile memory as it is, and combines the count value with the absolute angle detection value of the precision absolute angle detector.